Even myself which I am a person who does enjoy the occasional PVP sets find this achievement to be a bit over the top. This achievement makes it feel like we are forced to pvp just to be able to enjoy the fact of having completed something such as the meta meta achievement.
I understand as well with it being a meta it is not supposed to be easy yet the issue with this part of the achievement is that you have very poor odds on being able to accomplish this aside from the fact of having up to 79 people against you trying to get it themselves (everyone from both sides) or just griefing you to frustrate you. This does not promote a desire to pvp in fact it produces the opposite effect.
Not even the Christmas time pvp is this extremely difficult to obtain. This achievement does not rest on a persons ability to do something, but the extreme luck involved with being the first to get something. As well when you introduce the lag that can happen in even the best situation with this being something you can only work on for 1 week each year it seems unnecessary extra difficulty is added for no other reason than it seems Blizzard prefers their customers very frustrated and constantly tempted to drop their sub from aforementioned frustration. I certainly doubt that this is the case however the impression is there all the same.